The present invention concerns a method for the pneumatic splicing of threads or yarns containing an elastomer.
The present invention also concerns a device for the pneumatic splicing of the above-mentioned threads or yarns containing an elastomer.
Splicing devices for textile yarns are known which make use of compressed air, commonly defined as air splicers.
These devices have guides to facilitate the introduction of the threads to be spliced, means for clamping and cutting the threads, means for preparing the ends, means for withdrawing the cut threads in the direction of the chamber and a chamber created in a body and provided with a longitudinal slot for introducing and extracting the threads, wherein there are one or more holes or nozzles for injecting compressed air. In these devices, splicing of the threads is performed by means of the following operations, after having introduced into the device, and in particular into the splicing chamber, the ends of the threads to be spliced.
Firstly the threads are clamped and cut, after which the ends of the thread are opened, thus removing the twisting of the threads, by means of compressed air, and the ends of the thread are withdrawn in the direction of the chamber.
At this point the threads, with their fibres opened and lying parallel, are partly overlapping, one next to the other, and are then subjected to one or more jets of compressed air in the splicing chamber to perform the actual splicing. Finally the thread thus spliced is released and all the parts of the splicing device return to their original position.
On this subject it must be noted that, in recent years, yarns with a cut fibre containing an elastomer have become increasingly common on the market.
These yarns are usually made with techniques known as xe2x80x9ccore-spunxe2x80x9d and, applying certain precautions, such as the use of suitably labyrinths, they may be spliced with the technique described above, even if the elastomers contained in each of the two threads to be spliced cannot be interlaced with each other because of their single-filament nature. Another problem in splicing thread containing elastomer lies in the fact that, at the time of cutting the thread, the elastomer in the thread tends to shrink back due to its elasticity which is much greater than that of the spun fibres that surround it.
As a result, usually, splicing is performed on a piece of thread without elastomer and the spliced part remains without elasticity.
The aim of the present invention is, therefore, to provide a method and a device which allow splicing to be obtained in which the elastomers of the two ends of the thread to be spliced are incorporated.
This and other aims are achieved by a method for pneumatically splicing two threads or two yarns containing an elastomer, said method comprising the sequence of the following steps:
(a) introducing ends of said threads or yarns to be spliced into a splicing chamber (11), of a splicing device (10, 10a, 10b, 10c);
(b) inputing compresssed air by a first input of one or more jets of compressed air into said splicing chamber (11) to cause a first interlacing of said threads or yarns;
(c) cutting the ends of said threads or yarns with scissors (18, 19), after the said first input of compressed air to form threads or yarns having cut ends;
(d) inputing into said splicing chamber (11) a second input of one or more jets of compressed air to complete the splicing of said threads or yarns having cut ends and form a spliced thread or yarn;
releasing said spliced thread from said splicing device (10, 10a, 10b, 10c).
These aims are also achieved by a device for the pneumatic splicing of two threads or two yarns containing an elastomer, said device comprising a splicing chamber (11) having one or more holes or nozzles for injecting compressed air, a pair of suction ports (14, 17), each for one of said threads or yarns to be spliced, cutting means (18, 19) for said thread or yarns comprising at least one pair of clamping means using clamps (20, 21, or 22, 23) for clamping said ends of the threads or yarns to be spliced.
Further characteristics of the present invention are also defined in the subsequent claims.